In this tutorial I will walk through how a crawl space can be turned into a nice conditioned storage space.
When most people here the word crawl space they think of a musty cold damp dark place. Well this does not have to be the case. With some simple techniques and a couple hundred dollars you could save money on energy costs and add additional storage space.
This project was to insulate a 8' x 14' crawl space that was part of a master bedroom addition. The crawl space was a mess with debris on the floor and a huge arachnid population. The crawl space was sealed from the outside of the house but did have vents that were covered with dirt and a layer of foam board. The person / company that built the master bedroom addition decided to drywall over the access window in the basement to the crawl space. The new home owner did not realize that there was a crawl space until they felt cold air coming into one of the basement closets.
When I found the access it was an original basement window. After using a vacuum for awhile to clean out the initial mess I climbed in an looked around. The climb into the crawl space was outrageous. It was up above the basement floor about five feet. Once I got up into the window it was down about a foot and a half to the dirt floor. However, the crawl space was nice and roomy with about a three foot high ceiling.
The insulation that was installed was nowhere near the specs to keep the master bedroom floor warm and so I removed the 3/4" Dow board and started from scratch. There was plastic on the floor over the dirt, however, it wasn't all covered and had holes in it. This old plastic was removed and replaced with new vapor barrier.
For the time being the home owner opted for a quick fix, so I installed better insulation to keep the floor warmer (R-18 Mirflex by Owens Corning). I also installed a new layer of 6 mil vapor barrier on the floor to keep moisture from entering the crawl space through the ground. From the coloring on the blocks in a corner of the crawl space there looked to be some outside drainage problems. To correct the drainage problem I extended the downspouts out further away from the house. I also slopped the ground away from house to allow run off to drain further from the foundation.
The initial project was completed in 2001 and since then energy prices have risen. So it's now 2006 and the homeowner wanted me back to fix the problem (cold floors in master bedroom) for good. I suggested that we open the crawl space up and condition the area as if it was part of the basement. To condition the area I ran duct work off the furnace to heat and cool the crawl space. Opening it up will allow the homeowner to use the space as storage.
The first step was to get the size of the opening larger so that someone could fit in through the opening and use the crawl space as storage. I removed two rows of cement blocks using a small sledge hammer and a air chisel. This got the bottom of the opening down low enough so that a small step stool is all that is need to climb into the crawl space. The second step was to remove the tack strip around the perimeter that attached the 6 mil vapor barrier up onto the wall perimeter. Then I pulled back the vapor barrier so that I could level out the dirt for the new flooring. Once the ground was level I then relaid the vapor barrier.
The next step was to lay the floor. I laid 2x4 sleepers on the vapor barrier in order to screw the 1/2" plywood into a secured material.Sandwiched in between the vapor barrier and the 1/2" plywood is 2" foam board with foil face material on one side. The foil is placed face up so that the radiant heat is bounced back into the room and does not transfer out through the ground. Since the home owner is going to use this space as a storage area I will install a light and light switch inside the crawl space.
After the floor was finished I then installed the 2" foam board (foil faced in towards the room) to the side walls. I only needed to install the foam board onto three of the four walls because there is no need for insulation on the wall that separates the crawl space from the the main basement.
As seen in this photo the new fluorescent light is in and working. The fluorescent light, lights the whole crawl space without any additional fixtures.
The next step was to seal all seams and finish up the insulation part. I removed the ceiling insulation because it is not needed. I recycled some of the ceiling insulation and used it in the rim joists. I estimated that for the rim joists there is an R28-R36. My estimation for the walls are an R12-R18. Note: There is perimeter insulation on the outside of the house and the ground also act like an insulator. The old recessed crawl space vents were also insulated from the inside. On the outside I cleaned the recessed vents out and added a piece of form board in front of them. I then poured concrete into the recessed holes so that water will not be able to easily enter. To condition the crawl space I extended the duct from the adjacent room into the crawl space. The adjacent room had two registers and I was able to use one of them for the crawl space ventilation.
This is the finished entrance into the crawl space. The door was a complete modification. It started out as a standard size six panel door from Lowes. I was able to not have to modify the hinge side of the door. I cut the door off at the top and bottom. Then I installed a generic handle pull for opening the door. Since the door was hollow I had to reinforce the top, bottom, and handle pull. To do this I sprayed some foam spray inside the door and cut off the excess flush. The foam spray hardens up to give the door a solid feel. Note: I used triple expanding foam for this. However, I would not use it again because it bowed the door out in a small area at the top and bottom. By no means can you tell. I recommend using a spray foam made for door and windows.
Finished! As you can see it is filling up with boxes and storage bins. This was an excellent project that benefited the owner in more ways than one. Not only are they saving money on heating and cooling bills but they also gained 312 cub/ft of storage area.
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